1, mold -related knowledge Introduction
our daily production and life to the various tools used and products , large machine tool base, body shell , an embryo as small screws , buttons and various household appliances shell , are all closely with the mold relationship . Shape of the mold determines the shape of these products , mold processing will determine the quality and accuracy of the quality of these products . Because a variety of products, materials , appearance , specifications and use of different mold into a casting mold, forging mold, die casting mold, stamping mold and other non- plastic molds and plastic molds. In recent years , with the rapid development of the plastics industry in general and the strength and precision engineering and other aspects of continuous improvement , plastic products is also expanding range of applications , such as: household appliances, instruments , construction equipment, automotive , Japan Hardware and many other fields , the proportion of plastic products is rapidly increasing . A rational design of plastic parts can often replace multiple traditional metal pieces . Industrial products and household products plastic trend on the rise.

2, the general definition of the mold : in industrial production , with a variety of presses and mounted on a dedicated press tool , by the pressure of the metallic or non-metallic material the desired shape of the parts or products, such special tools collectively referred to as the mold.

3, the injection molding process description : Mold is a tool for the production of plastic products . It consists of several groups of components parts, this portfolio of successful mold cavity . When injection molding , the injection molding machine mold clamping , molten plastic is injected into the mold cavity and cooling in the cavity shape, and then separate the upper and lower molds , through the top of the system the article away from the top of the mold cavity , and finally the mold is closed again, the next injection , the entire injection molding process is recurring .

4, the mold generally classified : can be divided and non- plastic mold plastic mold :

(1) non- plastic molds are: casting mold, forging mold, stamping mold, die casting mold. A. Casting mold - taps, cast iron platform B. Forging Die - Automotive Body C. Stamping die - Computer panel D. Die Casting - super alloy , the cylinder body

(2) plastic mold production technology and production according to the different products are divided into : A. Injection Molding - TV cabinet, keyboard buttons ( the most common ) B. Blow molding - drink bottles C. Compression molding - Bakelite switch, science bowl dish D. Transfer molding - IC products E. Swage die - glue tubes, plastic bags F. Thermoforming mold - Transparent molded shell packaging G. Rotational molding - soft doll toy

◆ Injection molding is the most widely used plastics processing methods . The method is applicable to all thermoplastics and thermosetting plastics parts , obtained the large number of plastic products is unmatched by other molding methods , injection molding process as one of the main tools of injection molds, precision in terms of quality , manufacturing cycle and the injection molding process in terms of the level of production efficiency , direct impact on product quality, yield , cost and product updates , as well as a determinant of business competition in the market responsiveness and speed.

◆ injection mold is composed of several steel plates with a variety of component parts , basically divided into : A molding device ( die , punch ) B positioning device ( guide post, guide sleeve ) C fixtures ( the word board, code mode pits ) D cooling system ( carrying water hole ) E thermostatic system ( heating pipe, heater ) F runner system ( jack Tsui Kong , runner slot , runner hole ) G ejection system ( thimble , top stick )

5, according to the gating system made ​​of different type of mold can be divided into three categories :

(1) large outlet die : runner and gate at the parting line , with the product in the open mold with the mold , the most simple design , easy processing , low cost, so comparing multiplayer with large outlet system operations.

(2) fine nozzle mold : runner and gate are not parting line , usually directly on the product , so to design a set of multi- outlet parting line design is more complex, processing more difficulties , generally depending on product requirements Using fine nozzle systems.

(3) hot runner mold : mold structure with such a fine nozzle much the same, the biggest difference is the flow channel at a constant temperature of one or more of the manifold plate and hot squirt mouth, no cold material release , runner and gate directly on the product , so that no mold flow , this system is also called non- outlet system can save raw materials , raw materials for more expensive , higher product case , design and processing difficulties, the high cost of the mold . hot runner system , also known as hot runner system, mainly by the thermal gate sets , hot runner plate , thermostat electrical box composition. The most common hot runner hot runner system has a single point and multi-point thermal gate two kinds of forms . Single-point hot runner sprue bushing with a single hot molten plastic injection directly into the cavity , it applies to a single gate single cavity plastic mold ; multi-point thermal gate hot runner plate through the molten material to the respective branches of hot sprue bush in re-entering into the cavity , which applies to single-cavity multi-point or multi- cavity mold feeding .

◆ advantages of hot runner system

(1) no outlet material , no post-processing , so that the whole molding process is fully automated , saving time and increasing efficiency.

(2) the pressure loss is small. Hot runner injection molding machine nozzle temperature equal to the temperature , avoiding the surface of the material in the sprue condensation , the injection pressure loss is small.

(3) outlet material reuse plastic will degrade performance , but did not use the hot runner system outlet material , can reduce the loss of raw materials , thereby reducing production costs. Temperature and pressure in the cavity uniform , plastic stress, density, the smaller the injection pressure, the shorter time molding , injection molding system than the general better products . For the transparent parts, thin pieces , large plastic parts or plastic parts demanding better show its advantages, but smaller models can be used to produce large products.

(4) hot nozzle using standardized, serialized design, with a variety to choose from a nozzle head , good interchangeability . Unique design and processing of electric heating coil can be achieved by heating temperature, long service life. Hot runner system with manifold plate , thermostat , etc. , compact design, species diversity, easy to use, stable and reliable quality .

◆ hot runner system applications inadequacies

(1) to increase the overall height of the mold is closed , due to the installation of hot runner plate , etc., increase the overall height of the mold .

(2) thermal radiation is difficult to control , hot runner runner biggest problem is the heat loss is a major issue to be resolved .

(3) the presence of thermal expansion , thermal expansion and contraction are our issues to consider when designing .

(4) mold manufacturing cost increases , hot runner system standard accessories higher prices affect the popularity of hot runner mold